Skype is stepping up its mobile advertising game. The Microsoft-owned company is introducing a rich media mobile placement for iPhone today in select markets and plans to bring advertising to its Android app later this month.   Mobile is a growing area of the Skype business, according to Lovina McMurchy, gm of Skype Advertising. A third of the company's 300 million monthly users access Skype on mobile, she said, and Skype's Android app recently hit its 100 millionth download. "The move to mobile, that is where we see our future," McMurchy said, noting that the company had ...